The present invention relates generally to material handling systems and, more particularly, to vacuum generator for vacuum cup assemblies of material handling systems that are engaged with the objects and substantially sealed thereto via operation of a vacuum source or pneumatic device connected to the vacuum devices. It is known to provide a material handling system that includes vacuum cups or the like that are adapted to be moved into engagement with an object, such as a substantially flat object or panel or the like, and to lift and move the object to a desired location. Such vacuum cups or suction cups may be moved into engagement with the object, and a vacuum source may be actuated to create a vacuum between the object and the cup such that the object is retained to the cup as it is transported to the targeted area.
It is known, in order to reduce cycle times in industrial production lines, to provide vacuum generators having arrangements for the active release of objects from vacuum grippers, which grippers rely on negative-pressure or vacuum for gripping and moving the object. A solution that has been put into practice is to allow compressed air into the vacuum gripper or into a line that supplies vacuum to the vacuum gripper, typically via a controlled valve, in order this way to interrupt the vacuum which holds the object to the vacuum gripper means. This is generally, and in particular herein this disclosure referred to as so-called “blow-off”. Another known solution is to connect the vacuum gripper or the supply line with atmospheric pressure, via a controlled valve. This latter solution is not considered in this disclosure.
Both of these solutions is herein this disclosure referred to as “vent a vacuum cup”, i.e. deactivate vacuum.
Even if the firstly mentioned solution typically provides a reasonable fast release, this solution may however in some applications be too rough when fragile objects are concerned. In such applications the skilled person is typically limited to use the last mentioned solution, which however not always provides the desired fast response and may therefore hamper the rate of production.
Prior art devices are known from e.g. EP-B1-2263011 where it is disclosed a vacuum generator, driven by high-pressure air, and having means arranged for active release of an object that is gripped in a vacuum-gripper.
Although presently used systems have many advantages the used devices, the time to vent the vacuum cup, is in some occasions considered too long.
The object of the present invention is to achieve an improved vacuum ejector device that eliminates, or at least mitigates, the above stated drawbacks, by being more user-friendly to handle, and having shorter deactivation times.